×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Simulating Wind Tunnel Experiments- Test Facility nozzle and constant

Simulating Wind Tunnel Experiments- Test Facility nozzle and constant

Simulating Wind Tunnel Experiments- Test Facility nozzle and constant

(OP)
I am curious about what exactly the limits of Flow Simulation are for SolidWorks. I was working on a thesis (completed and cleared) which was to analyze a scramjet isolator scaled up for 10 and 100 times the cross section. The initial CFD analysis was to simulate M=1.8 airflow entering from a C-D (converging-diverging) nozzle into a scramjet isolator.

The overall CFD results matched the experiemnts however I was not getting the correct contour plots for the flow. In scramjet isolator operation, there is supposed to be a normal shock train which develops. (I posted link of what should be seen on page 252.)

Now the simulation had a constant exit pressure boundary condition. The experiment itself used a throttled valve to control the back pressure (i.e. increases the pressure values as it closes).

This comes to my question, is flow simulation capable of creating a boundary condition which can increase the pressure to a maximum at an inlet or exit for a time dependent simulation? This parameter is essential for simulating back pressure and creating the shock train. This should also be within the high Mach flow conditions for Flow Simulation.

RE: Simulating Wind Tunnel Experiments- Test Facility nozzle and constant

You can create time-dependant boundary conditions.  Not sure if that's what you're looking for, or if you're looking for a boundary that changes in response to some other variable in the study.  I *think* that's possible too, but it's beyond the scope of what I know how to do.

Anyhow, to make the BC a function of time, click the Fx button next to where you would input a constant property value.  You should get a 'dependency' window pop-up.  At the top of the window will be a drop-down for Constant, F(time) - table, or Formula Definition.  I'm not sure how to use 'Formula Definition' (never had to), but entering a table of time and BC values is easy enough.  Note that if you haven't yet set the study to be time dependant, the F(time) - table option will not be available.

All this is based on Solidworks/FloWorks 2008.  Exact method may vary in future versions.
 

RE: Simulating Wind Tunnel Experiments- Test Facility nozzle and constant

(OP)
No that helps alot, I was trying the f(x) command to simulate the initial conditions inside the airflow, but never could get the correct mach number and pressure for the B/C with respect to time.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources